Toripalimab is a recombinant, humanized programmed death receptor-1 (PD-1) monoclonal antibody that binds to PD-1 and prevents binding of PD-1 with programmed death ligands 1 (PD-L1) and 2 (PD-L2). Rituximab is an antibody to CD20 molecules. One of the mechanisms of killing tumor cells is through antibody-dependent cell-mediated cytotoxicity (ADCC). These two drugs may have a synergistic effect on anti-tumor. The purpose of this study is to determine whether Toripalimab with Rituximab is effective and safe for treatment of relapsed refractory CD20 positive diffuse large B-cell lymphoma. This is an exploratory small sample, phase II, single-center clinical trial, which is going to enroll 20 participants.
